Accurate optical spectra of semi-conductors and insulators

Our BAND developers in Toulouse published a simple yet accurate method to obtain accurate optical spectra for semi-conductors and insulators.

In a recent Phys. Rev. B paper they combine time-dependent DFT with the dynamical Polarization functional using the ground state density obtained from the GLLB-sc model potential. The polarization function accurately predicts excitonic effects without any parameter (Phys. Rev. Lett. 115, 137402 (2015)), while the explicit calculation of the difference between the fundamental gap and the Kohn-Sham band gap with the GLLB response potential, as implemented in ADF,  leads to a much more accurate optical gap, i.e. a better onset of the optical spectrum.

Thus, by linking a parameter-free TDDFT exchange-correlation kernel with a parameter-free model potential for the ground state density, a Pure Kohn-Sham method is obtained which accurately predicts optical spectra for semi-conductors and insulators.

S. Cavo, J. A. Berger, and P. Romaniello, Accurate optical spectra of solids from pure time-dependent density functional theory, Phys. Rev. B 101, 115109 (2020)